Knowledge of hydraulic control valve control system
Professionals from excavator parts manufacturers explain to us the knowledge of hydraulic control valve control system. The hydraulic control valve control system is divided into the following parts: 1) Pilot type control system The control form of the reversing control valve has direct-acting type (direct control of the main spool of the reversing valve with a handle, currently rarely used) and pilot type. The latter uses the pilot valve to control the pilot oil, and then uses the pilot oil to control the main spool of the reversing valve. It is divided into two types: mechanical-hydraulic pilot type and electro-hydraulic pilot type. 2) Load sensing control system 'The valve control system is essentially a throttling system. Nowadays, on hydraulic excavators, the general three-position six-way multi-way valve is commonly used, and its slide valve has poor fine-tuning performance and compound operation performance. Since the 1990s, the load sensing control system has been adopted on hydraulic excavators, and its control flashes are equipped with pressure compensation valves regardless of whether it is in the open-centered or closed-centered manner. Compared with the traditional hydraulic system of hydraulic excavators using electronic control pressure compensation, the main advantages of the load sensing control system are: (1) save energy consumption. Regardless of whether some ordinary three-position six-way reversing valves use a fixed pump or a variable pump, a part of the oil will always overflow through the overflow valve, which wastes energy. However, using the load sensing variable system, the flow of the pump is all used for the load, and the pressure of the pump is only 1-3 MPa larger than the load pressure. (2) The excavator has high flow control accuracy and is not affected by changes in load pressure. (3) Several actuators can move synchronously or at a certain speed ratio without interfering with each other. Professionals from excavator parts manufacturers especially remind that some ordinary three-position six-way valve systems use parallel oil circuits. When several actuators act at the same time, the oil output by the pump first flows to the actuator with low pressure and cannot be synchronized.